<p>i registered for us subject test</p>
<p>and i want to change it . .so on the test day i am able to do that ... i want to change it to math</p>
<p>butttt is it possble for me to take both us and math on sat. when i only registered for one sat ii ?</p>
<p>Yes, it's possible to either switch to math, or to take both history and math. If you're adding an exam, you may need to talk to the proctor beforehand and fill out some sort of form, and the Collegeboard will bill you for the extra exam.</p>
<p>or you can call the collegeboard tomorrow and change it through them</p>
<p>I am in the same situation as you are! Although I am still a bit unsure if I will take both or just switch US to Math II</p>